Amisulpride is a member of the chemical class benzamide, and has the chemical name 4-amino-N-[(1-ethylpyrrolidin-2-yl)methyl]-5-ethylsulfonyl-2-methoxy-benzamide. The chemical structure of amisulpride is as follows:

There is a need for better treatments of psychiatric and mood disorders, including bipolar disorder and in particular depression associated with bipolar disorder. For example, psychiatrists indicate that about 25% of patients across all bipolar disorders are refractory during a manic episode, while about 70% are refractory during a depressive episode. Thus, there is a need for drugs that remit depressive symptoms in bipolar patients.
Dopamine receptor antagonists are one class of drugs used to treat psychiatric disorders, however efficacious D2 occupancy levels are also related to deleterious side effects. A need also therefore exists for central nervous system drugs (CNS) and in particular psychiatric drugs for the treatment of depression and diseases and disorders with a depressive component, that provide a therapeutic effect with no or reduced side effects and in particular side effects associated with dopamine D2 receptor occupancy.
Racemic amisulpride is sold under the tradename Solian® as 400 mg tablet and as a solution for the treatment of acute and chronic schizophrenic disorders, in which positive symptoms (such as delusions, hallucinations, thought disorders) and/or negative symptoms (such as blunted affect, emotional and social withdrawal) are prominent, including patients characterized by predominant negative symptoms, with a recommend total daily dose of 400-800 mg. However, movement related adverse events including tremor, rigidity, hypokinesia, hypersalivation, akathisia, dyskinesia are listed as “very common” in the label for racemic amisulpride in the 400-800 mg/day dosage range. Such as extrapyramidal symptoms are commonly associated with antipsychotic drugs employing dopamine receptor blockade. Typically, extrapyramidal symptoms are observed at high dopamine receptor occupancy, e.g., at about 70-75% occupancy. Other side effects associated with racemic amisulpride include prolongation of the QT interval and increase in prolactin which may lead to galactorrhoea, amenorrhoea, gynaecomastia, breast pain, erectile dysfunction. Therefore, there is need for better psychiatric drugs with reduced side effects.
A need exists for an amisulpride composition which has reduced adverse events and a greater safety profile. A further need exists for an amisulpride composition which can effectively treat bipolar symptoms accompanied with depression more effectively than current formulations. A still further need exists for an amisulpride formulation which is optimized to antagonize the D2 dopamine receptor associated with bipolar symptoms and separately optimized to antagonize the 5-HT7 serotonin receptor associated with symptoms of depression.